Two Sparks, One Flame
by Cyndaquil255
Summary: Isabella is about ready to go see what Phineas and Ferb are up to when she notices it's July 24th, the day her rivals, Fireside Girls Troop 37295 come to town.  Thing quickly erupt into conflict.  And what's Doof up to with sports equipment?  R&R, Please.
1. An Old Rival Returns

**Phineas and Ferb and it's theme songdo not belong to me. Phineas and Ferb belongs to Dan Povenmire and Jeff "Swampy" Marsh, and I'm PRETTY sure the theme song belongs to Bowling for Soup.

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Chapter 1

**An Old Rival Returns**

_There's 104 days of summer vacation, 'till school comes along just to end it,_

_So the annual problem for our generation is finding a good way to spend it._

_Like maybe_

_Building a rocket, or fighting a mummy, or climbing up the Eiffel Tower._

_Discovering something that doesn't exist (Hey!), or giving a monkey a shower._

_Surfing tidal waves, creating nano-bots, or locating Frankenstein's brain. (It's over here!)_

_Finding a dodo bird, painting a continent or driving our sister insane! (PHINEAS!)_

_As you can see, there's a whole lot of stuff to do before school starts this fall. (C'mon, Perry!)_

_So stick with us cuz Phineas and Ferb are gonna do it all!_

_So stick with us cuz Phineas and Ferb are gonna do it all! (Mom! Phineas and Ferb are making a title sequence!)_

It was another beautiful day in Danville. The sun was shining, the birds were singing, and you could hear the sounds of construction work coming from the backyard of one particular house. This house was where Phineas Flynn and Ferb Fletcher live. However, our story does not begin there, but rather, across the street at the home of Isabella Garcia-Shapiro, Phineas' girlfriend. She had just woken up, and was just about ready to go see what Phineas and Ferb were up to today. "Alright, Pinky. I'll see you later on, okay?" Pinky, her Chihuahua, just barked in response, but Isabella knew he was trying to tell her, 'Okay, you have fun!' She glanced over at her calendar as she walked out of the room. "Oh, July 24th. We'll be back in school soon." Just as she was about to close the door, her eyes went wide. "Wait, wait, wait. It can't be July 24th yet, can it? Please, please, PLEASE, tell me I'm hallucinating!" But as she got a closer look at the calendar, she saw it really was the 24th of July. "Oh no. Oh no, no, no!" She rushed out of her room without shutting the door, and shouted in horror, "PHINEAS!"

Across the street, Phineas and Ferb were hard at work on something when Isabella showed up, looking quite frantic. Phineas, concerned for his girlfriend, asked, "Hey, Izzy, is everything alright?"

"No, Phineas, it's not! Do you know what day it is today?"

"…Thursday?"

"NO! Well, yes, but that's not what I meant! Phineas, it's July 24th! JULY 24th, PHINEAS!"

"WHAT? It's that day already? Oh, man, I can't believe I forgot! Alright, Ferb, we need to put this rocket on hold! Something much more-"

Just then, Candace came outside. "What are you guys up to?" she asked in her usual tone.

"Oh, hi Candace. Well, we WERE building another rocket, but Isabella needs to get away from Maple Drive for today. Chelsea's coming back to Danville today!" Phineas replied frantically.

"Chelsea? You mean that girl that used to live up the street? I thought you guys used to be- wait. Did you say you're building another rocket? I thought you already did that!"

"Well, we did, but we figured we'd take our friends to see our star. You know, the milkshake bar with the really bright sign? STILL can't believe how bright that was."

"Well I'm staying here. And I'm telling mom! You guys are so busted this time!" Candace went back inside to call her mom, as Phineas, Ferb, and Isabella left the backyard.

"Hey Ferb, did you see Perry this morning?" Ferb just looked back over the fence towards the tree, where Perry had been moments before. He then pointed over towards it, to which Phineas responded, "Oh, I get it. He was under the tree but now he's not. Well, Izzy's more important right now."

Meanwhile, Perry had wandered back into Phineas and Ferb's bedroom. He took a quick look around, and, not seeing anyone, put on his fedora and re-arranged some of the books on their bookshelf. Ferb's bed lifted up, revealing a chute. He hopped right on, and actually slid down pretty fast. In fact, he came down the chute so fast, he actually flew right off the end and into his chair, which spun around several times, causing Perry to get dizzy. His boss, Major Monogram, said, "Sorry about that, Agent P. Our slide waxing guy went a little overboard with the wax this morning. Anyway, your mission. Doofenshmirtz was seen heading toward City Hall with boxes filled with sporting equipment earlier today. We're not sure what he's up to, given his poor athletic ability, but it's probably no good. Get to the bottom of it." Perry saluted Monogram, hopped into his hover car, and headed off to City Hall to see what Doofenshmirtz was up to. As he flew over the city, he saw a familiar van with a Fireside Girls emblem on the side. Knowing who was coming and what she brought with her, Perry silently wished his owner and his girlfriend luck with what they were about to deal with.

_Doofenshmirtz in the Mayor's Office!_

Doofenshmirtz walked into the Mayor's Office in City Hall holding the boxes of sports equipment. He set it down and went over to his brother, Roger. "Hello, Roger," he said, with a hint of resentment in his voice.

"Heinz, what's with the sports equipment? If you're here to ask me to come play football or baseball or whatever, it'll have to wait until later. I'm very busy right now. And besides, you're not very athletic,"

"Oh, will you be quiet! I'm here to challenge you to a series of sporting events to prove that I am clearly the 'Alpha-male' as some might call it. And I'm not taking no for an answer!" Just then, Perry burst through the door. Not literally, of course. Perry has respect for the mayor's property! "Perry the Platypus? What are you doing here? Oh, oh the sports equipment? No, that's not part of an evil scheme. It's just regular old sports stuff. Go on, see for yourself!" Perry walked over to the box, pulling out a baseball bat. After pulling a baseball out as well, and tossing it up in the air a few times and swinging at it, he determined that since he was able to miss, it hadn't been modified in any way, shape, or form. "See, see? I just have this stuff because I need to prove to Roger that I'm better at SOMETHING than he is! And I've been practicing, too! Still, if you're not totally convinced that I'm not up to no good, you can stick around and observe." Perry just stood there, and gave him a look that said 'Yeah, alright.'

Meanwhile, back on Maple Drive, Buford, Baljeet, and yes, even Irving, had shown up to see what Phineas and Ferb were up to today. "Nothing right now, guys. Really, we need to get Isabella away from here before… THEY show up."

Buford, Baljeet, and Irving were confused. "Who are 'they?'" Baljeet asked, curious.

"'They' are the most annoyingly obnoxious people ever! They're Fireside Girls, like me, but for some reason, their leader hates me! And every year, they come by on the 24th of July just to spend the day harassing me! Well, their leader does, anyway. She's just so mean…"

There came a voice from down the street a bit that said, "Do I hear you bragging about me, Isabella?" Isabella froze, stiff as an ice sculpture, while everyone else turned to see who it was. There, coming up the street, were six girls, all in Fireside Girls uniforms. What was unique about these girls compared to other Fireside Girls, though, was that they wore uniforms that were mostly red, with little bits of orange, as opposed to the usual orange with a little red. The girl in front was about as tall as Isabella was, with blond hair worn in a pony tail, and a smug look on her face. Her uniform had an orange collar, but other than that, it was solid red. When they reached the group of friends, they stopped, and the girl said, "It's been a while, hasn't it. I hear you've got yourself a boyfriend now. I'm actually surprised about that. Who would want to date you?"

"That would be me," Phineas said, glaring at her.

"Oh, yes. I remember now. She's liked you for years, Phineas. I would've preferred it if you hadn't noticed her, actually."

"For your information, Chelsea, I told him how I feel. It happened on the Summer solstice, right after we flew around the world in 40 hours."

"Ooh, wow. You finally decided to be brave? Should've kept it to yourself."

"UGH! Chelsea, why are you always doing this to me? What did I do?"

"You know perfectly well what you did!"

"Who is this, Phineas?" Irving asked, out of the blue.

"Oh, you haven't told your friends about me? Well, I guess I should get introductions out of the way. Chelsea Jameson, leader of Fireside Girls troop 37295, at your service! These are my troop members." Chelsea pointed to each girl, saying their names as she went. "Shannon," she said, pointing to a girl with simple brunette hair, who was slightly shorter than her. Her uniform had thin orange stripes on it. "Alexis," she pointed to another blond, this one with her hair looking like Candace's, and slightly taller than her. Her uniform had orange sleeves and an orange collar.

"CHELSEA! I told you, NEVER call me Alexis! How many times do I have to tell you, I prefer Alex!"

"Err, right, Alex. Anyway…" She pointed to a girl with orange hair next. It was curled up in the back, and tied with a green bow at the end. Her uniform was almost completely red, with very thin orange cuffs on the ends of the sleeves. "This is Tori." Then she pointed at another brunette, with shoulder-length hair with two blue bows in it, who was around the same height as Shannon. Her uniform had an orange line on the bottom. "Marissa." Then she patted the last one on the head. She had blonde hair as well, only it was down over her shoulders. Her uniform had two thick orange stripes running along the middle of it. She looked similar to Chelsea, except she was a little shorter. "And this is my little sister, Jessie."

Isabella wasn't exactly thrilled to see them. She wouldn't mind them so much if Chelsea wasn't there, but she was, so, she wasn't in a good mood. "Yeah. Hi."

"Oh, c'mon, Isabella. They seem like nice kids!" Baljeet said, earning a look of confusion from Isabella.

"Nice? Did you NOT hear what I said about them earlier?"

Chelsea wanted Isabella to leave. She just couldn't stand her for reasons she refused to disclose to anyone, even her sister. "Isabella, why don't you just run down to your lodge and talk to your pathetic troop of Fireside Girls."

"PATHETIC? Chelsea, you haven't SEEN any of the things we've done! We've traveled through time, we helped Phineas and Ferb build a giant Papier-mâché airplane, and sent a van off of the rollercoaster at the old abandoned Old Abandoned Amusement Park to get a Maracanut tree so we could get the sap for Phineas and Ferb's super durable bubble! We're anything BUT pathetic!"

"Yeah, okay, Isabella. Listen, just go get your troop, and meet us back here at 10. If you don't show up, don't worry. We'll find you." Chelsea snapped her fingers, then said, "Girls." Her troop followed her away from Phineas, Ferb, and their friends, as Isabella just stood there, boiling mad that Chelsea had called her and her troop pathetic.

"Hey, Izzy, maybe you should go see your troop. Maybe they can do something about this this year."

Isabella calmed herself down, then said, "Alright. Will you come to the lodge with me, Phineas?"

"Absolutely. Ferb, Buford, Baljeet, Irving, why don't you guys stay here and try thinking up something to help us." Ferb just gave a thumbs up in response. Phineas and Isabella headed off towards the lodge while Ferb, Buford, Baljeet, and Irving went inside to think.

Back at the mayor's office, Roger was busy with his work. Doofenshmirtz didn't like this; he wanted to get on with the sports competition he had set up. "Come ON, Roger! What's with you? You always used to love sports, especially kickball!"

"Look, Heinz. I'm very busy right now. But if you insist, I'll join you as soon as I finish my work. Why don't you go play catch with that… what ever it is," he said, referring to Perry. Doofenshmirtz groaned, then went over and took a seat next to Perry.

"Ugh, Roger gets on my nerves so much, Perry the Platypus. Which is why I'm determined to beat him at something today. But waiting for him to finish his work is asking too much! I mean, look at all those papers! Luckily, I came prepared. Behold, Perry the Platypus, the Fast-Forward-inator!" Doofenshmirtz pulled out a small ray gun that looked similar to the Slow-Motion-inator. "Remember the Slow-Motion-inator from earlier this summer? It's like that, but instead of slowing you down, it makes you speed up until you finish what you're doing. See, I just set this dial to say, 4 times speed, and…" He pulled the trigger, which fired a ray right past Perry's bill, causing him to jump and accidentally toss his baseball out the window. The ray hit Roger, and he started working on his paperwork 4 times faster than he had before. "See, Perry the Platypus? He'll be finished in no time. And I have more baseballs where that came from." Perry just chattered, as usual.

Meanwhile, the baseball bounced down into the street, where it hit a car, was flung over to the park, and hit by a kid with a baseball bat. The ball flew a fair distance, was hit by another car, and then bounced off the side of a truck. Eventually, the baseball happened to reach Phineas and Ferb's backyard, where it landed, by complete coincidence, on the launch button for their unfinished rocket. The rocket lifted off, but because it was incomplete, it exploded in mid-air, leaving no trace it ever existed. And wouldn't you know it, Candace shows up just then with her mom. "Look, look, see? They built a rocket ship!"

"Candace, I don't see anything but a baseball. How does that look like a rocket ship?"

"But…. But it wasn't even finished this time! It never vanishes until they're done using it!"

"Well, if that's all, I'm going back to the mall." As her mom left, Candace just stood there, mouth agape. She was so sure that since it wasn't finished, she'd be able to show her mom the rocket. But even that vanished, too.

Elsewhere in Danville, Phineas and Isabella were on their way to the Fireside Girl lodge. Isabella was hanging her head, upset at Chelsea's return. Phineas noticed this, and asked her, "What's up, Izzy? You seem upset."

Isabella looked over at her boyfriend, and said, "Oh, it's just Chelsea, Phineas. She irritates me. All she ever does is make fun of me, sabotage my troop's efforts to earn patches, and just plain be mean to me. This is the one day of the year I never look forward to. I wish I could just stay in bed all day. Maybe then I wouldn't see her. I know whatever she has planned, it's just going to end up humiliating me in some way. It always does. And she won't even tell me why she does these things!"

"Hey, Izzy, c'mon. I know that someday, you'll beat her at something. That's just the kind of girl you are. You keep trying if you fail. I mean, look how long it took for us to end up as boyfriend and girlfriend. But you never gave up on that, did you?"

"Well….. No, I guess not…"

"Exactly. And you shouldn't give up on this, either. That wouldn't be the Isabella that I love." Phineas gave her a quick kiss, and as her spirits lifted, Phineas could tell she wasn't ready to give in on this just yet. "So, you gonna keep trying, or what?"

Isabella, now in a much better mood, said "Absolutely! Now let's go, Phineas! Hmm. I wonder if the Fireside Girls know Chelsea's here yet." They continued walking and soon enough, the Fireside Girl lodge came into view. They walked inside, and found troop 46231 inside, patiently waiting for Isabella to show up. "Alright, girls, come to order." The girls all sat down, and waited for what Isabella was going to say. "Now, as you all know, today is July 24th, the day our rivals, troop 37295, lead by Chelsea, who hates me for reasons unknown, come to town. They want us to meet them on Maple Drive at 10. For what, I'm not sure. But whatever it is, I know they're going to try to humiliate me. However, we may be able to turn the tables if we try. After all, we haven't given up in the past 4 years, so why start now? Alright, any questions?" Adyson raised her hand. "Yes, Adyson?"

"Won't this just go in a cycle? Like if we beat her, she'll try to beat us at something else?"

Phineas spoke up at that. "Well, I could go set something up with Ferb that could be like a competition of sorts. You know, to prove who's truly the better troop? I'd need time to work on it, though."

"Excellent! You go see Ferb about that, Phineas. This time, Chelsea's goin' down."

**To be continued**

**When Isabella said her and Phineas became boyfriend and girlfriend on the Summer Solstice, she was referring to my oneshot, "Summer Belongs to You Aftermath." Give it a look if you haven't already, it's pretty good.**


	2. Plans for a Competition

**I'M NOT DEAD! HORRAY!**

**Sorry this took so long. But now I can take this story off of it's temprary hiatus! Okay, so I know this chapter isn't as long, and it's kinda dry in my opinion, but I hope you like it.**

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Chapter 2

**Plans for a Competition**

Back at the mayor's office, Perry watched as Roger continued to zip through his paperwork. He had finished half of it already, and it had only taken him about 30 minutes! Despite the fact that Doofenshmirtz was his nemesis, he had to admit, using the Fast-Forward-Inator to speed Roger through his work was a good idea.

"You see, Perry the Platypus? It's nothing harmful or anything, all it does is enable him to finish all his work faster. And it's only just 10 now! Starting at 10:30 won't be so bad, I'll still have plenty of time to do this competition with Roger." Perry chattered at Doofenshmirtz again. He was convinced Doofenshmirtz wasn't doing anything evil today, but he was still going to stick around, just to be on the safe side.

_Back at Maple Drive…_

Phineas, Isabella, and Fireside Girls troop 46231 arrived in front of Phineas and Ferb's house. A quick look around showed Chelsea and her Fireside Girls weren't here yet.

"Alright, I'm going inside to talk to Ferb about this. Will you be okay out here, Izzy?"

Isabella nodded. "Yeah, I should be fine. Besides, if I need you, you're right inside."

"Alright, well, Chelsea will be here any minute now. Don't let her get to you." Phineas opened the door and stepped inside his house. Ferb, Buford, Baljeet, and Irving were sitting on the sofa, thinking. "Hey guys. You come up with anything yet?"

Ferb shook his head. Buford responded, "I don't know how you guys come up with these things every day."

"Well, it helps to have such an active imagination. Anyway, I came to tell you guys, I may have a solution to our problem involving Chelsea."

Irving, curious, asked, "Phineas, how exactly does this 'Chelsea' know you guys? I've never heard of her, and I know almost everything about you guys!"

Phineas responded, "Oh, don't worry about it that much, Irving. She used to be my-" at that moment, Candace came into the living room. She was on her cell phone with Stacy, as usual.

"-and it was just gone! It doesn't make any sense! It wasn't even done yet!"

"Who knows, Candace. Maybe fate just doesn't want you to bust your brothers."

"I don't know about THAT, Stacy. But I just get so frustrated with it! The rocket was- Uh, hold on a second." She covered the receiver of the phone. "What are you guys up to now?"

"Well, we're going to be doing something to help Isabella with her little problem with Chelsea."

"….Stacy, I'll call you back." She hung up the phone, then raised a quizzical eyebrow at the kids. "What do you mean? You already did something today. It's not very often you do two things in one day, unless they're directly related."

"Well, as I was saying, I thought that maybe Isabella, Chelsea, and their troops of Fireside Girls could have a competition of some sort to see who can earn the most patches today. We just need to build a stadium and everything. You can help if you want to, Candace."

"What are you, kidding? When have I EVER helped you guys with anything? Okay, so I went with you guys around the world. But that wasn't helping, I was just going because I was in charge of you guys, and I wanted to see Jeremy."

"Alright, suit yourself, sis." Phineas sat down on the couch next to Ferb and said, "Alright, so, a competition, then. All we need to do is decide which patches to include so we can build the stadium accordingly." Phineas looked deep in thought. "Hmmm…."

Candace glanced over at Phineas. "Why are you so concerned about this, anyway? If you want her to leave your girlfriend alone, just go ASK her. You guys used to talk all the time."

"It's not that easy, Candace. Chelsea has had it out for Izzy for four years now. And don't you remember? When she came by 3 years ago, she seemed not to even notice me, or at least care that I knew her. I doubt she even wants to have anything to do with me at all."

"Well, okay then. Just out of curiosity, how come you have to think about which patches to put in the competition? You seemed to have an easy time helping me earn those 50 to see the Paisley Sideburn Brothers."

"Well, yeah, Candace. But we can choose ANY of the patches for this! For you, we had to pick the 50 you could get fastest. Plus, there's loads of patches that they already have! We can't just pick a patch out of the book! They might already have it!"

"Well, then, looks like you have to go talk to them, then. Go on, go outside. I'm going to call Stacy back. Later." Candace opened her phone, dialed Stacy, and left the room. Phineas, Ferb, Buford, Baljeet, and Irving sat in silence for a moment.

Phineas spoke up, "Alright, well, before we go find out which patches they can compete for, we should start drawing up some blueprints for the stadium itself. Let's get to work!"

_Elsewhere in Danville…._

Chelsea, Jessie, and their friends were on their way to Maple Drive. They were still a ways away, though. They walked in silence, with Chelsea in the front of the group, Jessie following close behind, and Alex, Tori, Marissa, and Shannon close behind her.

Jessie broke the silence, asking Chelsea, "Hey, Chelsea? Can I ask you something?"

Chelsea turned to look at her sister. "Look, sis, I love you, but I am NOT telling you why I hate Isabella so much."

"How come? We're sisters, Chelsea. We tell each other everything. As far as I know, you hate her just because you feel like it. Please? Just tell me."

Chelsea sighed. "I'm sorry, Jess, but I don't want to tell anyone. There is a reason, but I just…. I don't want anyone to know why."

"Fine, then. But I don't see why you hate her." Jessie fell back a bit from Chelsea, upset that her own sister wouldn't tell her her biggest secret. For as long as she could remember, they've always told each other everything. Jessie even knew how Chelsea felt about Ferb. Not even their parents know about that.

Alex spoke up, "Hey, don't let it get to you, Jess. I'm sure Chelsea has her reasons for not wanting to tell you."

"Well, yeah, but it hurts me that she won't, Alex. I mean, really, she tells me everything except for this."

"Just forget about it for now, Jessie. I'm sure she'll tell you eventually." Jessie smiled at Alex, and then looked back forwards. She could see Phineas and Ferb's house now, and she was hoping that whatever plan Chelsea had for Isabella, it'd be over quick. Despite her sister's hatred of Isabella, Jessie still thought of Isabella as a friend, and Isabella still sees Jessie as a friend, as well.

Back inside Phineas and Ferb's house, they were busy working on the blueprints. They had drawn up a large portion of the structure of the stadium, and were almost ready to go ask Isabella and Chelsea which patches they still need to get. Phineas looked at the blueprints and said, "Alright, Ferb. I guess we should go outside and see if-"

Phineas didn't finish his sentence, because outside, he heard Isabella scream "UGH! LOOK WHAT YOU DID, CHELSEA!" Phineas rushed outside and saw Isabella laying in a large mud puddle with Chelsea close by, laughing like a hyena.

Chelsea, in the midst of her laughter, let out, "Oh, Isabella! That is SO not what I intended to do, but it's so much BETTER! Look at yourself!" Chelsea was laughing so hard, tears were actually beginning to spill from her eyes. From the ground, Isabella shot a death glare at her rival as Phineas helped her up. Ferb and the others had made it outside by now, and everyone around was glancing disapprovingly at Chelsea, even Buford.

Isabella brushed most of the mud off of her outfit, stomped over to Chelsea, whose laughter had started dying down, and glared right into her eyes. "Chelsea, you've made a fool of me for the last time. I swear, if it's the last thing I do, I'm gonna crush you."

Chelsea returned the glare, and responded mockingly, "Oh, really? And how exactly do you intend to do that? You seem to forget: I've been beating you out for the past 4 years now."

Isabella continued glaring at Chelsea. "Chelsea, I challenge you and your troop to a competition to see which troop can earn the most patches fastest."

Chelsea's expression changed to one of shock for a moment, before returning to the smug look she always wore around Isabella. She snickered, then responded, "Fine. But don't you go crying to your boyfriend when we're the ones who crush YOU!" Chelsea and Isabella stayed glaring at each other. As they did so, Troop 46231 and Troop 37295 glanced on, with upset expressions on their faces. They were beginning to doubt that the two would ever get along…

_In the Mayor's office once more…_

Roger was nearing the completion of his work Perry had gotten another baseball, and had been tossing it at the wall for about half an hour, and Doofenshmirtz had been sitting patiently while waiting for Roger to quickly finish his work. "Okay, Perry the Platypus, he's almost done. Y-you should probably put the baseball back now." Perry looked at him, then complied and put the ball back in the box. He then looked over at Roger, who was about to finish his work.

As he stood up, Roger said, "Wow, I finished that work a lot faster than I thought I would. Okay, Heinz, I guess we can go now." Doofenshmirtz picked up the box of sports supplies and left the building with Perry and Roger.

As they walked down to the park, Doofenshmirtz said to Perry, "Really, Perry, you could go if you want. I'm not up to anything. Although, I could use an extra hand with this sports thing with Roger. Some of these sports are gonna need an extra hand so that it's not such a burden on us to like go get the baseballs every time we swing and miss or something like that. Could you help?" Perry chattered and gave Doofenshmirtz a thumbs up, indicating that he would help. "Oh, thank you, Perry the Platypus! There's got to be at least one thing in here that I can beat Roger at. Look at him, he thinks he's so tough. But I'm gonna beat him at something today, I just know it!" Perry continued walking on towards the park, half expecting Doofenshmirtz to reveal one of his -inators at a later point of the day.


End file.
